Morpholine Solution Separation of Reactive Adhesive Layered Films

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Solution Overview

Problem

Existing methods struggle to easily separate and recover layered films laminated with reactive adhesives from plastic-based complex waste, as the strong crosslinking adhesive layer formed by thermoset resins makes it difficult to separate the individual layers.

Innovation Solution

A method involving immersion of the layered film in a morpholine solution with a concentration of 50% or more, heated or ultrasonically vibrated, to reduce the adhesive force and facilitate the separation of single-layered films, specifically using a morpholine solution with additives like alkaline solutions and surfactants to effectively peel off the adhesive layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a reactive adhesive containing polyisocyanate and polyol is used to laminate resin films, then the adhesive strength and retort resistance are improved, but the separability of the layered film becomes difficult

Engineering Contradiction:
Improveadhesive strengthVSAvoidseparability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

A morpholine solution is introduced as an intermediary substance to facilitate separation of the crosslinked adhesive layer. The morpholine solution penetrates the adhesive layer and reacts with the crosslinked structure, acting as a chemical mediator that breaks down the strong adhesive bonds without damaging the resin films themselves

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The physical and chemical parameters of the adhesive layer are changed by treating it with morpholine solution under controlled conditions (temperature, concentration, time). This transforms the crosslinked adhesive from an insoluble, strongly bonded state to a separable state, enabling easy delamination while preserving film integrity

Inventive Principle:
Principle #35Parameter changes

2Reliability

If thermosetting resins are used in layered films, then the thermal resistance and structural stability are improved, but the recyclability through thermal decomposition becomes difficult

Engineering Contradiction:
Improvethermal resistanceVSAvoidrecyclability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Morpholine solution serves as a chemical intermediary that enables recycling of thermosetting resin-based layered films. Instead of relying on thermal decomposition, the morpholine solution chemically modifies the crosslinked adhesive, allowing mechanical separation and reuse of the resin films without thermal degradation

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The conventional thermal decomposition method is replaced with a chemical treatment method using morpholine solution. This substitution avoids the high temperatures required for decomposing thermosetting resins, enabling gentle recycling that preserves the quality of resin films while achieving separability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Strength

If the adhesive layer is strongly crosslinked to improve lamination strength, then the bond durability is improved, but the ease of separation into single-layered films deteriorates

Engineering Contradiction:
Improvebond durabilityVSAvoidease of separation
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The adhesive layer is preliminarily treated with morpholine solution before separation is attempted. This preliminary chemical treatment weakens the crosslinked structure in advance, creating conditions that allow easy separation while maintaining the original bond durability during the service life of the laminated product

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The chemical parameters of the adhesive layer are changed by controlled exposure to morpholine solution, which selectively modifies the crosslinked adhesive without affecting the resin films. This parameter change transforms the adhesive from a strongly bonded, inseparable state to a separable state while preserving film properties

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method allows for efficient separation and recovery of layered films, enabling the classification and reuse of plastic-based complex waste, even when laminated with reactive adhesives, by significantly reducing the adhesive force and allowing for interfacial peeling without dissolving the films.

Implementation Method 1

immersing the layered film in a morpholine solution having a morpholine concentration of 50% by mass or more while stirring the layered film with heating at 20°C to 90°C or ultrasonically vibrating the layered film

Methodology Applied
Scientific EffectChemical interaction with morpholine solution:

Implementation Method 2

immersing the layered film in a morpholine solution having a morpholine concentration of 50% by mass or more while stirring the layered film with heating at 20°C to 90°C

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 3

immersing the layered film in a morpholine solution having a morpholine concentration of 50% by mass or more while stirring the layered film with heating at 20°C to 90°C or ultrasonically vibrating the layered film

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Data Source

PatentEP3854841B1Method for separating and recovering layered film
Publication Date: 2023.07.26 DIC CORP

AI summary

A method for separating and recovering a layered film laminated and adhered with an adhesive, the method including a step 1 of immersing the layered film in a morpholine solution having a morpholine concentration of 50% by mass or more while stirring the layered film with heating at 20°C to 90°C or ultrasonically vibrating the layered film and a step 2 of recovering separated single-layered films that constitute the respective layers of the layered film. The adhesive is preferably a reactive adhesive containing a polyisocyanate composition and a polyol composition.